The present invention relates generally to leads for conducting electrical signals to and from the heart. More particularly, it pertains to an electrode having conductive fixation features for delivering electrical charges to and from the heart.
Cardiac rhythm systems are used for treating an irregular or unstable heart. The systems include, among other things, pacemakers which deliver timed sequences of low electrical energy to the heart, such as via a lead having one or more electrodes. Leads have been implanted in the body for electrical cardioversion or pacing of the heart. More specifically, electrodes implanted in or about the heart have been used to reverse (i.e., defibrillate or cardiovert) or sense certain life threatening arrhythmias, or to stimulate contraction (pacing) of the heart, where electrical energy is applied to the heart via the electrodes to return the heart to normal rhythm.
Cardiac pacing and/or sensing may be performed by the transvenous method or by electrodes implanted directly onto the epicardium. Traditionally, to attach a lead epicardially, a thoracotomy is performed where the thorax is opened to obtain access to the heart. This procedure involves painful and expensive surgery for the patient. Transvenous pacing may be temporary or permanent. In temporary transvenous pacing an electrode catheter is introduced into a peripheral vein and fluoroscopically positioned against the endocardium.
Traditional permanent transvenous pacing is performed under sterile surgical conditions where an electrode is positioned in the ventricle or atrium through a subclavian vein, and the proximal terminals are attached to a pulse generator which is implanted subcutaneously. The distal tip of the lead is positioned within an apex of the heart to hold the lead in place. Leads which are implanted in the apex of the heart have a backstop, which assists in preventing the lead from floating, and allows for the distal end of the lead to become fixated therein. Potential complications induced by the presence of the lead within the chambers of the heart, however, can preclude lead implantation of the lead within the chambers of the heart.
One approach to resolve this issue is to implant the lead transvenously. When a lead is implanted transvenously, the passage has no termination into which the lead can be positioned, resulting in a floating lead. One of the drawbacks of a floating lead is that the performance of the electrical interface between the electrode and the tissue can be diminished. In addition, the veins or arteries are filled with blood, surrounding the electrode, which further inhibits the electrical interface between the electrode and the tissue.
Defibrillation, which is used to treat a heart which is beating too quickly, delivers a high energy electrical stimulus which allows the heart to reestablish a normal rhythm. In addition to a defibrillating electrode can be combined with a pacing and/or sensing electrode. To obtain lower pacing and sensing thresholds, the pacing/sensing electrode is traditionally disposed at the tip of the lead, which is positioned deep within an apex of the heart at the largest center of mass of the heart. To minimize sensing problems following a shock from the defibrillating electrode, the defibrillating electrode is separated away from the sensing/pacing electrode on the lead. As the defibrillating electrode is moved away from the tip of the lead, however, the shock strength requirement increases resulting in increased demands on the battery of the cardiac rhythm system.
Accordingly, there is a need for an implantable lead that is capable of placement and fixation in other regions of the heart, such as within vascular structures. In addition, there is a need for a lead having an electrode for positioning within a passage, such as a vein or artery, that allows for fixation of the lead. There is also a need for a body implantable lead which allows for effective stimulation from a defibrillation electrode. There is further a need for a lead that is capable of effectively defibrillating the heart, and also pacing/sensing the heart in a limited area.
The present invention relates to a lead assembly having a lead body extending from a distal end to a proximal end, and includes a conductor. The lead assembly further includes an electrode assembly of at least one electrode, and the electrode assembly is electrically coupled with the conductor. The electrode assembly has an electrically conductive tine adapted for fixating the lead assembly within tissue. In one embodiment, the tine has a first end coupled with the lead body and a second end which extends away from the lead body.
In another embodiment, the tine is formed of an electrically conductive material, for instance, conductive silicone. In another embodiment, the conductive tine includes a conductive coating. In yet another embodiment, the conductive tine is molded to the conductor. The conductive tine further optionally includes one or more non-conductive tines adapted for fixating a portion of the lead assembly. In addition, a defibrillation electrode is disposed at the distal end of the lead body in another embodiment.
In one embodiment, the lead assembly, which has a lead body extending from a distal end to a proximal end, includes a conductor. The lead assembly further includes an electrode assembly of at least one electrode, and the electrode assembly is electrically coupled with the conductor. The electrode assembly has an electrically conductive cone adapted for fixating the lead assembly within tissue. In one embodiment, the cone includes a conductive ring disposed on a distal end of the cone.
In another embodiment, a lead assembly has a lead body extending from a distal end to a proximal end, and includes a conductor. The lead assembly further includes an electrode assembly of at least one electrode, and the electrode assembly is electrically coupled with the conductor. The electrode assembly has an electrically conductive tine adapted for fixating the lead assembly within tissue. A conductive member is disposed within a portion of the conductive tine and is electrically coupled with the electrode assembly.
In one embodiment, the conductive tine includes a partial coating of nonconductive material. In another embodiment, a plurality of conductive tines are provided. The conductive member, in one embodiment, is a wire. In another embodiment, the conductive member is a flat wire or a foil. In yet another embodiment, the conductive tine extends from a first end proximate to the lead body to a second end disposed away from the lead body, and a conductive cap is at the second end of the conductive tine.
In another embodiment, a lead assembly is disclosed which has a lead body extending from a distal end to a proximal end, and includes a conductor. An intermediate portion of the lead body has a straight lead body. The lead assembly further includes a conductive fixation feature which extends away from the lead body. The conductive fixation feature is a protrusion which extends from the intermediate portion of the lead body, and includes an electrode. In one embodiment, the electrode is a sensing or pacing electrode. In another embodiment, the conductive fixation feature is a conductive tine. In addition, the tine includes a cap coupled with the tine in another embodiment. In yet another embodiment, a non-conductive tine is coupled with the lead body and is adapted for fixating a portion of the lead assembly within tissue.
In yet another embodiment, a lead assembly has a lead body extending from a distal end to a proximal end, and includes a conductor. A defibrillation electrode is electrically coupled with the conductor, and is disposed at a second end of the conductor forming a defibrillation tip at the distal end of the lead body. The lead assembly further includes, in another embodiment, a second defibrillation coil disposed at an intermediate portion of the lead body. In addition, the lead assembly includes an electrically conductive tine coupled with a portion of the lead body, in one embodiment. The conductive tine optionally has a first end coupled with the lead body and a second end which extends away from the lead body. In another embodiment, the conductive tine is partially covered with non-conductive material. A conductive bead, in one embodiment, is coupled with a distal end of the conductive tine. In another embodiment, the tine is electrically common with the defibrillation electrode. An electrical discharge surface, in a further embodiment, is disposed between the second defibrillation coil and the distal defibrillation tip, where insulation is optionally disposed between the conductive tine and the defibrillation coil.
A lead assembly, in another embodiment, has a lead body extending from a distal end to a proximal end, and includes a conductor. The lead assembly further includes an electrode assembly of at least one electrode, and the electrode assembly is electrically coupled with the conductor. The electrode assembly has a plurality of electrically conductive tines adapted for fixating the lead assembly within tissue, and the conductive tines are retractable. In one embodiment, the tines have a first end extending from a hinge point and a second end which extends away from the hinge point, where the conductive tine flex at the hinge point. In a retracted position, the retractable tines are disposed in a lumen of the lead body. In an extended position, the retractable tines are extended out of the lumen.
In another embodiment, a lead assembly has a lead body extending from a distal end to a proximal end, and includes a conductor. The lead assembly further includes an electrically conductive fitting coupled with the conductor. An electrode assembly is coupled with the fitting. The electrode assembly including an electrically conductive tine is adapted for fixating the lead assembly within tissue and is molded to the fitting. In one embodiment, the tine is formed of a conductive polymer. In another embodiment, the tine is formed of a conductive rubber or elastomer.
In yet another embodiment, a lead assembly has a lead body extending from a distal end to a proximal end, and includes a conductor. The lead assembly further includes an electrode assembly of at least one electrode, and the electrode assembly is electrically coupled with the conductor. The electrode assembly has a conductive fixation feature which is adapted to send and receive electrical signals. The conductive fixation feature extends from a first end to a second end and includes a flexible and conductive intermediate portion between the first end and the second end. The intermediate portion is flexible away from the conductor. In one embodiment, the first end of the conductive fixation feature is coupled with the lead body and the second end is movably coupled with the lead body. The lead assembly further includes, in another embodiment, a locking mechanism adapted to maintain the intermediate portion in a flexed position. In another embodiment, the locking mechanism includes a slider movably disposed within a slot, and an interference slot sized to engage the slider. The slider is coupled with the second end of the conductive fixation feature. The lead assembly further includes a deployment mechanism, in another embodiment. Examples of deployment mechanisms include a wire or a balloon catheter.
Another embodiment is a lead assembly which has a lead body extending from a distal end to a proximal end, and includes a conductor. The lead assembly further includes an electrode assembly of at least one electrode, and the electrode assembly is electrically coupled with the conductor. A sheath of conductive material is disposed over the electrode assembly. The sheath, in one embodiment, is formed of a conductive polymer. In another embodiment, the sheath is formed of a conductive urethane. In one embodiment, the electrode assembly comprises a defibrillation coil.
In yet another embodiment, a system for delivering signals to the heart includes an electronics system including a cardiac activity sensor and a signal generator for producing signals to stimulate the heart, and a lead assembly. The lead assembly has a lead body extending from a distal end to a proximal end, and includes a conductor. The lead assembly further includes an electrode assembly of at least one electrode, and the electrode assembly is electrically coupled with the conductor. The electrode assembly has an electrically conductive tine adapted for fixating the lead assembly within tissue. The tine has a first end coupled with the lead body and a second end which extends away from the lead body. In one embodiment, the tine is formed of a conductive polymer. In another embodiment, the tine is formed of a conductive polymer, rubber, or elastomer. The conductive tine, in one embodiment, includes a conductive coating. In yet another embodiment, the conductive tine is molded to the conductor. The conductive tine further optionally includes one or more non-conductive tines adapted for fixating a portion of the lead assembly. In yet another embodiment, the conductive tine is a wire extending away from the lead body.
These and other embodiments, aspects, advantages, and features of the present invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art by reference to the following description of the invention and referenced drawings or by practice of the invention. The aspects, advantages, and features of the invention are realized and attained by means of the instrumentalities, procedures, and combinations particularly pointed out in the appended claims and their equivalents.